Jamieson, Fausset and Brown on Habakkuk 1:13

13. purer ... than to behold evil--without being displeased at it.

canst not look on iniquity--unjust injuries done to Thy people. The prophet checks himself from being carried too far in his expostulatory complaint, by putting before himself honorable sentiments of God.

them that deal treacherously--the Chaldeans, once allies of the Jews, but now their violent oppressors. Compare "treacherous dealers," (Is 21:2; 24:16). Instead of speaking evil against God, he goes to God Himself for the remedy for his perplexity (Psa 73:11-17).

devoureth the man that is more righteous--The Chaldean oppresses the Jew, who with all his faults, is better than his oppressor (compare Eze 16:51, 52).